The present invention relates to a composite structure for a hockey stick.
Hockey stick systems have traditionally been made from wood. Wood has been a convenient and traditional material to use but is limited in strength and weight. The wood stick is solid and can be made from a multi ply lamination in order to improve strength.
Recent developments have improved hockey sticks by making them out of metal such as aluminum. Such sticks are typically made from a one piece extruded aluminum tube to which can be attached a blade and handle. The tubular construction offers a lighter weight and also easy attachment for the blade and handle.
More recent developments have advanced hockey stick performance by using composite materials such as fiber reinforced resins such as carbon fiber in an epoxy resin. These sticks are tubular in form to maximize strength and minimize weight.
Composite materials are attractive alternatives to wood, because there exists a large selection of fiber types and resin types, the combinations of which can produce a multitude of options suitable for replacement to wood. These composite laminates have the advantage of being stiffer, stronger, and less susceptible to environmental changes than wood.
One of the first patents describing composite materials used for hockey sticks is U.S. Pat. No. 4,086,115 to Sweet which discloses a tubular hockey stick manufactured using fiberglass fibers in a polyester resin made using a pultrusion process.
U.S. Pat. Nos. 5,419,553 and 5,303,916 to Rogers disclose an improved hockey stick made from composite materials, also made using the pultrusion process, with the addition of specific fiber orientation in order to improve the stiffness and strength of the stick.
The pultrusion process has also been used to create a hockey stick of two tubes with an internal wall in between. U.S. Pat. Nos. 5,549,947, 5,688,571, 5,888,601, 6,129,962 to Quigley, et. al., describe a continuous manufacturing operation to produce a hockey stick with continuous fiber reinforcement. The limitations of making a hockey stick using a pulltrusion process are that fiber placement cannot be changed along the length of the structure and the cross-section cannot be varied along its length.
U.S. Pat. No. 5,636,836 to Carroll, U.S. Pat. No. 5,746,955 to Calapp, U.S. Pat. No. 5,865,696 to Calapp, and U.S. Pat. No. 6,241,633 to Conroy all describe tubular hockey stick systems made from fiber reinforced resin materials with specific fiber orientation in order to achieve desired performance characteristics.
There exists a continuing need for an improved hockey stick system. In this regard, the present invention substantially fulfills this need.